Why the exception "Object reference not set to an instance of an object." occurs?

[hurrem]

Hi, I have a question, I very often get exceptions like: Object reference not set to an instance of an object. Why does it occur? for exmaple in this code: SDSCheckUser.SelectCommand = "SELECT [newuser] FROM [Users] WHERE [username] = "+username; DataView view1 = (DataView)SDSCheckUser.Select(DataSourceSelectArguments.Empty); bool newuser = (bool)view1.Table.Rows[0].ItemArray[0]; Thanx

[Christian Graus]

It means one of your casted objects returned null. You keep getting it because the code is poor - it should always check return values.

Christian Graus - Microsoft MVP - C++ "I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

[daniel__c]

could be because if there is no user that matches the username there won't be any data at Table.Rows[0].ItemArray[0]....well that seems the most likely anyways.